package download;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.tomcat.util.codec.binary.StringUtils;
import org.apache.tomcat.util.http.fileupload.IOUtils;

/**
 * Servlet implementation class DownloadServlet
 */
@WebServlet("/DownloadServlet")
public class DownloadServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public DownloadServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		        request.setCharacterEncoding("utf-8");
                response.setCharacterEncoding("utf-8");
		        //获得请求文件名
				String filename = request.getParameter("filename");
				System.out.println(filename);
				
				//设置文件MIME类型
				response.setContentType(getServletContext().getMimeType(filename));
				//设置Content-Disposition
				response.setHeader("Content-Disposition", "attachment;filename="+filename);
				//读取目标文件，通过response将目标文件写到客户端
				//获取目标文件的绝对路径
				String fullFileName = getServletContext().getRealPath("/download/" + filename);
				System.out.println(fullFileName);
				//读取文件
				InputStream in = new FileInputStream(fullFileName);
				OutputStream out = response.getOutputStream();
				
				//写文件
				int b;
				while((b=in.read())!= -1)
				{
					out.write(b);
				}
				
				in.close();
				out.close();
			}
			
	 
	
	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}
